Production of Blue Natural Food Coloring From Butterfly Pea Flower Extract ( Clitoria ternatea Linn.) by Osmotic Membrane Distillation and Freeze‐Drying

ABSTRACT This research explores osmotic membrane distillation (OMD) and freeze‐drying (FD) as methods of concentrating the butterfly pea flower ( Clitoria ternatea Linn.) extracts to produce food coloring rich in anthocyanins. The OMD experiments were conducted at varied feed temperatures, draw solution (DS) types, and DS concentrations to determine the effect of each parameter on water vapor permeate flux. Feed temperature is the most significant parameter, while types and concentrations of DS do not have any significant effect on permeate flux. The OMD and FD showed excellent preservation of phenolic concentration, antioxidant activity, and color spectrum of the produced natural food colorant, A straightforward techno‐economic assessment estimated the manufacturing cost to be $65.30/kg powder after four‐fold concentration with OMD combined with freeze‐drying, which value was 53.29% lower compared to direct FD.